PURPOSE: To obtain the zoom lens for a video camera which consists of a small number of lens and has a wide angle and is small in size and low in cost by composing the lens of a 1st, a 2nd, and a 3rd group, and varies the power and adjusts the image position by moving the 2nd and 3rd groups on the optical axis in mutually opposite directions while fixing the 1st group during power variation. ;CONSTITUTION: This zoom lens consists of the 1st group which is fixed during power variation and has positive refracting power, the 2nd group which has negative refracting power, and the 3rd group which has positive refracting power in order from an object side. This lens system varies the power and adjusts the image position by moving the 2nd group and 3rd group on the optical axis in mutually opposite directions and satisfies the conditions shown by inequalities I and II. The inequality I is 1.6β2T/β2wβ3T/β3wD5.0β2T/β2w and the inequality II is 0.05|f2|/f10.25, where f1 and f2 are the focal lengths of the 1st and 2nd groups, β2T and β2w are the powers of the 2nd group at the telephoto end and wide-angle end respectively, and β3T and β3w are the powers of the 3rd group at the telephoto end and wide-angle end respectively.;COPYRIGHT: (C)1994,JPO&Japio
展开▼
机译：用途：通过组合第一组，第二组和第三组镜头，获得一种摄像机镜头的变焦镜头，该镜头由少量镜头组成，具有广角，尺寸小且成本低廉，并且改变光焦度并通过在光轴上使第二和第三组沿彼此相反的方向移动，同时固定第一组光焦度来调整图像位置。 ;组成：该变焦镜头由从物方开始依次排列的第一组和第二组组成，第一组在屈光力变化期间固定，并且具有正屈光力，第二组具有负屈光力，第三组具有正屈光力。该透镜系统通过使第二组和第三组在光轴上沿彼此相反的方向移动来改变光焦度并调整图像位置，并且满足不等式I和II所示的条件。不等式I为1.6＆β 2 T /β 2w <＆beta; 3 T /β 3w D <5.0β 2 T /β 2w ，不等式II为0.05 <＆verbar; f 2 ＆verbar; / f 1 <0.25，其中f 1 和f 2 是第一组和第二组的焦距，β 2 T和 2w 分别是第二组在望远端和广角端的光焦度，而 3 T和β 3w 是第三组在望远端和广角端的力量。版权所有：（C）1994，JPO＆Japio
展开▼
